Alkyl mercaptomethylphosphonic acids



United States Patent 3,193,626 ALKYL MERQAPTQN THYLPHOSPHGNIC ACIDS George M. Calhoun, Cleveland, Ghio, assignor to Shell Gil Company, a corporation of Delaware No Drawing. Original application Apr. 13, 1959, Ser. No. 895,686, new Patent No. 3,112,271, dated Nov. 26, 1963. 'Divided and this application Aug. 39, 1963,

Ser. No. 305,809

2 Claims.

This patent application is a division of copending patent application Serial No. 805,686, filed April 13, 1959, and which matured on November 26, 1963, into US. Patent 3,112,271.

This invention relates to a new and novel class of organic Z-thia-methyl phosphono compounds. More particularly the invention is directed to esters of 2-thiamethyl phosphonic acid and their use as additives in various organic compositions such as oils, plastics, etc.

The invention is directed to 2-thia-alkyl phosphoruscontaining compounds having the general formula:

wherein R is a hydrocarbyl radical having at least 6 carbon atoms such as a saturated C1048 alkyl radical, or an arakyl or aryl radicals; the R s are the same or different C alkyl radicals or hydrogen, or amine, preferably an alkyl amine. Preferred compounds of the general Formula I have the following formula:

and of the above formulas it is preferred that the alkyl portion of the molecule be C1048 alkyl and wherein R is hydrogen or a short alkyl radical of 1-4 carbon atoms, A is an aliphatic amine, preferably a primary or secondary amine, such as C primary straight chain amines, e.g., octylamine, laurylamine, stearylamine, etc., or branched chain primary aliphatic amines, e.g., t-C alkylamine, such as t-c H17NH2, t-C H NH to ttCfiHgjNHg 0r C5 13 secondary aiiphatic amines, such as diamylamine, di-Z-ethylhexylamine, didecylamine, etc.

The Z-thiaalkylphosphonic compounds are prepared by reacting a mercaptan or mercaptide having at least 6 carbon atoms with a halomethylphosphono compound such as chloromethylphosphonic acid or chloromethylphosphonate or their thioderivatives in a suitable solvent, such as an aqueous alcoholic solution, at reflux temperature and under inert conditions until the reaction is completed which normally requires from 1 to about 5 days. The mercaptans include aliphatic mercaptans, such as hexyl, octyl, decyl, dodecyl, octadecyl mercaptans, cycloalkyl mercaptans, such as cyclohexyl mercaptan, dicyclohexyl mercaptan, aralkyl mercaptan;

such as phenyldecyl mercaptan, benzyl mercaptan and the like. Instead of the mercaptans, the mercaptides can be used such as the alkali metal (Na or K) mercaptides of the above compounds. Suitable halomethylphosphonic compounds include chloromethylphosphonic acid, mono or dihydrocarbyl chloromethylphosphonates, e.g., mono or dibutylv chloromethylphosphonate, mono or di-Z-ethylhexyl chloromethylphosphonate, mono or dilauryl chloromethylphosphonate, mono or diphenyl chloromethylphosphonate, mono or dicyclohexyl chloromethylphosphonate, mono or dibenzyl chloromethylphosphonate, dibutyl dithiochloromethylphosphonate, diphenyl chloromethyl dithiophosphonate, dibutyl chloromethyltrithiophosphonate, alkali metal salts such as Na and K salts of chloromethylphosphonic acid, Na and K salts of monobutyl chloromethylphosphonic acid, Na and K salts of monodecyl chloromethylphosphonic acid and the like.

'A preferred method of making the 2-thiaalkylphos phonates is to react a suitable mercapto compound, such as an alkali metal (Na or K) C1048 alkyl mercaptide with an alkali metal (Na or K) saltof chloromethylphosphonic acid in an alcoholic solution under reflux conditions and under an inert atmosphere to form the alkali metal salt of an alkylmercaptomethylphosphonic acid. The salt is then treated with a strong acid such as hydrochloric acid to spring the free alkylmercaptomethylphosphonic acid, which can be converted into desired partial or full esters of polyvalent metal salts or amine salts for use as oil, fuel and grease additives as well as other uses.

The following examples illustrate the preparation of additives for use in accordance with the present invention.

EXAMPLE I Stoichiometric amounts of the potassium salt of decyl mercaptan and monochloromethylphosphonic acid were dispersed in an aqueous solution of ethyl alcohol and the mixture was refluxed at 78 C. under a nitrogen atmosphere for about 1 day. The potassium decylmercaptomethylphosphonate was then treated with strong hydrochloric acid to spring the free phosphonic acid which was recovered by extraction with ether. The final product decylrnercaptomethylphosphonic acid analyzed as follows:

The procedure of Example I was followed except that potassium salt of phenylmercaptanwas used instead of potassium salt of decylmercaptan and the final product was phenylmercaptomethylphosphonic acid.

EXAMPLE In The dibutyl ester of decylmercaptornethylphosphonic acid of Example I was prepared by treating decylmercaptomethylphosphonic acid with butyl alcohol in an alcoholic solution at about and extracting the ester with ether. 7 1

EXAMPLE IV Di-Z-ethylhexylamine vsalt of decylmercaptomethylphosphonic acid (Z-thiadodecylphosphonic acid) was prepared by reacting the product of Example I with di-2- ethylhexylarnine in an amount sufiicient to completely Fatented Aug. 3, 1965 i neutralize both acid groups, at about 50 C. in an alcoholic solution and thereafter recovering the amine salt from the alcoholic solution.

EXAMPLE V Following the procedure of Example IV, the tert-octadecylamine salt of decylmercaptomethylphosphonic acid -was prepared using tert-octadecylamine, available commercially under the trade name of Primeme J M-R, instead of di-Z-ethylhexylamine.

The following additional compounds were prepared: octylmercaptomethylphosphonic acid, dodecylmercaptomethylphosphonic acid, cyclohexylmercaptomethylphosphonic acid, benzylmercaptomethylphosphonic acid, phenylmercaptomethylphosphonic acid, dibutyl decylmercaptomethylphosphonate, phenyldecylmercaptomethyl acid phosphonate, dithiobutyl dodecylmercaptomethylphosphonate, dibutyl phenylmercaptomethylphosphonate, phenyldecylmercaptomethyl acid phosphonate, dithiobutyl dodecylmercaptomethyphosphonate, dibutyl phenylmercaptomethylphosphonate, dithiooctyl cyclohexylmercaptomethylthiophosphonate, dioctylamine dodecylmercaptomethylphosphonate, dioctadecylamine phenylmercaptomethylphosphonate, tert-octadecylamine dodecylmercaptomethylphosphonate and mixtures thereof.

The additives of this invention are novel compounds. They are oil-soluble and can be used in amounts of from about 0.1% to about 25%, preferably from about 0.5%

'to about 5.0% by \weight.

Mercaptomethylphosphono compounds of this invention are outstanding additives for various liquid hydrocarbon products, such as natural and synthetic hydrocarbon lubricating oils, greases, fuels (gasoline, kerosene, gas oil, burner fuel oil), asphalts, waxes, slushing oil, industrial oils, e.g., metal working and drawing oils, quenching oils, textile oils, hydraulic oils, dielectric compositions and other industrial oils. They are particularly outstanding when added in small amounts to lubricating oils and lubricating compositions to impart extreme pressure and anti-wear properties to such materials. Also, these additives are useful additives for gasoline, fuel oils, and other light oil products.

The following compositions are illustrative of the invention, the percentages being by weight, of the indicated additive or additives with the remainder being essentially the base.

Composition A: Percent Example I additive 2 1010 mineral oil Balance Composition B:

Example II additive 2 1010 mineral oil Balance Composition C:

Example III additive 2 1010 mineral oil Balance Composition D:

Example IV additive 2 1010 mineral oil Balance Composition E:

Example II additive 1 SAE 30 mineral oil Balance Composition F:

Example I additive 2 SAE 90 mineral oil Balance Composition G:

Example I additive 2 Laurie acid 2 SAE 90 mineral oil Balance Composition H:

Example I additive 5 'Ucon 50HB660 (polyethylene propylene glycol having a SUS viscosity at 100 F.

of 660) Balance 4 Composition I:

Example I additive 2 Di-Z-ethylhexyl sebacate Balance Composition .1

Example I additive 1 Leaded gasoline (3 cc. of TEL) Balance Composition K:

Example I additive 0.1 Fuel oil (No. 2) Balance Compositions of this invention were evaluated for their extreme pressure properties on a Spur-Gear machine. The machine consists essentially of two geometrically similar pairs of gears connected by two parallel shafts. The gear pairs are placed in separate gear boxes, which also contain the supporting ball bearings. One of the shafts consists of two sections connected by a coupling. Loading is accomplished by locking one side of the coupling and applying torque to the other. The conditions of the test were:

Speed r.p.m 3200 Oil temperature C Oil flow-rate cc./scc 10 Load in increments 5 min. at each setting.

Results of the evaluations are given in Table I and for the purpose of comparison, the results obtained from the use o f ihe base oil alone and with other known extreme pressure compositions are also given.

Table I Composition: Score load, lbs/in. A through I 5,600 1010 mineral oil+2% C alkenyl succinic acid 1,400 1010 mineral oil +2% malonic acid 2,800 1010 mineral oil+2% 3-hexadecyl adipic acid 1,400 1010 mineral oil+2% dodecylmercapto succinic acid 1,400 1010 mineral oil+10% glycerol monooleate 1,800 1010 mineral oil+2% C13H27OH (Oxo process) 1010 mineral oil The following compositions were also tested for stability in the Dornt Oxidation Test described in the Natural Petroleum News, September 17, 1941, pages 294-6 under the following conditions: 302 F., iron catalyst, mineral white oil base and additive amount in each example was about 1% by weight and the results are shown in Table II.

The mercaptomethylphosphono compounds of this invention are useful also for providing superior load-carrying properties for lubricating oils which contain minor amounts of other agents, such as silicone anti-foaming agents, alkylphenol anti-oxidants, polyacrylate ester viscosity-index improvers, long chain fatty acids such as lauric and oleic acids, oiliness agents and the like.

I claim as my invention:

1. As a compound a C alkyl mercaptomethylphosphonic acid.

2. As a compound, decyl mercaptomethylphosphonic acid.

References Cited by the Examiner UNITED STATES PATENTS OTHER REFERENCES Arbuzov et al.; J. Gen. Chem. U.S.S.R. (English 0 translation), vol. 27, pp. 2419-2421 (1957).

CHARLES B. PARKER, Primary Examiner. 

1. AS A COMPOUND A C10-18 ALKYL MERCAPTOMETHYLPHOSPHONIC ACID. 